Such a ceiling support is known for example from U.S. Pat. No. 3,175,085.
To compensate the weight of a radiation source installed on the free end of the telescope or telescope arm, a cable is usually led through the telescope arm which is connected with a device for the compensation of the weight. Such a unit can for example include a cable winch driven by an electro motor. With this, however, the radiation source cannot be moved with the dynamics of a manually adjustable ceiling support.
Furthermore, to compensate the weight, devices are known which include a gas pressure or torsion spring. Such units have the disadvantage that the weight compensation is not constant over the total extension length of the telescope arm. Torsion springs have the further significant disadvantage of a relatively short lifespan.
In addition, it is known that a helical tension spring is used for the weight compensation and the cable is led over the spiral winch. Although this can be used to achieve an almost constant compensation of the weight over a wide section of the extension length of the telescope arm, a ceiling support using helical tension springs cannot be designed compactly. Moreover additional technical safety devices must be provided in case the helical tension springs break.